Electrostatic chucks are used for holding a workpiece in various applications ranging from holding a sheet of paper in a computer graphics plotter to holding a wafer within a semiconductor wafer processing chamber. Electrostatic chucks typically retain a workpiece (i.e., a semiconductor wafer) thereon, by creating an electrostatic attractive force between the wafer and the chuck. In particular, a voltage is applied to one or more electrodes in the chuck so as to induce oppositely polarized charges in the wafer and electrodes, respectively. The opposite charges provide an attraction force, which pulls the wafer against the chuck, thereby retaining the wafer.
In one type of wafer processing chamber, RF and chucking power has been provided to the one or more electrodes of the electrostatic chuck using a solid stainless steel rod, sequentially plated with copper, nickel, and gold. The solid copper plated rod is disposed though an insulating tube (e.g., fabricated from quartz), extending through the chamber to the chuck, where the solid copper plated rod is coupled to the chucking electrodes. However, the solid copper plated rod and quartz tube require an excessive amount of space within the shaft to accommodate the overall diameter of the tube to provide proper RF isolation. Furthermore, the solid copper plated rod is not flexible and the quartz tube is fragile and subject to being damaged during installation. As such, the manufacturing costs, parts replacement costs, and repair costs for a wafer processing chamber are driven higher.
Therefore, there is a need in the art for a high temperature resistant DC chucking and RF biasing cable having high RF voltage isolation.